Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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TABLE SAW GUARD ASSEMBLY
BACKGROUND
(0001] Typical table saws include a base or frame having a flat table top or
supporting a flat table top. The table top generally includes a slot through
which a
cutting member, such as a circular saw, protrudes above the table top. Often,
a
riving knife or sputter is mounted directly in line with the saw blade. The
riving
knife operates to keep separate the two sides of the portion of the workpiece
that
has been cut. By keeping the workpiece separated, it reduces the possibility
of the
workpiece binding as it is cut. Table saws also include a guard to protect the
operator from potential serious injury caused by accidental contact with the
saw
blade. The guard is located in such a way so that it prevents the operator
from
contacting the saw blade while in use.
[0002] Many types of riving knives and guard assemblies have been used in
the past. However, these,assemblies have often been difficult to use because
they
are typically quite flimsy and obstruct the operator's view of the workpiece,
or the
saw blade, or the reference marks or scales used to align the workpiece. As a
result, many guards are offen removed which in turn results in a higher
probability
of accidents and injuries. Additionally, the removal of guards from the table
saw
often requires the use of tools making the adjustment or maintenance of the
saw
blade and riving knife Complicated and difficult.
[0003] Accordingly, objects of the preseW invention include providing a table
saw having a riving knife/guaud assembly that. provides the operator with
protection from the blade; provides a clear view of the cutting or work zone,
the
workpiece to be cut, the saw blade, and any scale or alignment marks; allows
for
easy removal and installation of the guard without the use of any tools; that
can
easily accommodate different size workpieces; and is sturdy.
BRIEF SUMMARY
(0004] An improved riving knife/guard assembly is provided for use with a
table saw. The assembly includes a riving knife that is mounted to the table
saw
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frame in line with the caw blade. The riving knife i s adjustable directly
with the
blade so that as the blade height is adjusted to accommodate for different
size
workpieces, or the blade angie is adjusted for bevel cuts, the riving knife is
similarly adjusted.
~UUUS~ A guard is attached to the riving knife. ~Che guard is attached to the
riving knife using a system of one or more pins that engage slots on the
riving
knife. The slots can be dogleg shaped and oriented in opposing directions. At
feast one of the pins is a inulti-position pin that can be placed in at least
two
positions. In one position, the guard is securely and rigidly mounted to the
riving
knife. In a second position, the guard can be removed from the riving knife.
[0006) The guard also can be provided with a viewing slot that allows the
operator to see the cutting zone, and/or the workpiece that is being cut,
and/or the
saw blade, and/or any scale or alignment marks. To further enhance viewing,
the
guard can be provided with a light or a magnifying lens or both.
[0007] The guard may also include a bail. The bail may be pivotally mounted
onto the guard top plate. The pivot mounting allows the bail to be raised or
lowered and to also be movable to accommodate different size workpieces. The
bail may also be two-piece construction. This provides further flexibility for
accommodating different size workpieces and bevel cuts.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The features and advantages of the present invention may be better
understood by reference to the accompanying drawings in which like reference
numerals refer to like elements and in which:
[0009] FIG. 1 is a perspective view of an exemplary table saw incorporating
various features according to the present invention.
(0010[. FIG. 2 is a side view of a riving knife/guard assembly and saw blade
(removed from the table saw) incorporating various features according to the
present invention.
[0011) FIG. 3 is a top view of a riving knife/guard assembly incorporating
various features according to the present invention.
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j0012j FIG. 4 is a perspective view of an exemplary table saw incorporating
various features according to the present invention including a riving
knife/guard
assembly where the bail is in an up or lifted position.
j00I3J FIG. 5 is an exploded view of a riving knife/guard assembly
incorporating various features according to the pre sent invention.
[0014] FIG. 6 is a front view of a portion of a table saw, including the saw
btade, table top and riving knife/guard assembly incorporating various
features
according to the present invention.
(0015( FIG. 7 is a bottom view of a riving knife/guard assembly incorporating
various features according to the present invention.
[0016) FIG. 8 is a perspective view of a riving lrnifc, multi-position pin and
cecond pin incorporating various features according to the present invention.
[0017] FIG. 9 is a side view of a rivinglknife guard assembly incorporating
various features according to the prescut inveutiun.
[0018] FIG. IO is a front/top view of a guard top plate incorporating various
features according to the present invention, including a light and a
magnifying
lens.
(0019] FIG. 11 is a front view of a guard top plate incorporating various
features according to the present invention, including chamfered interior
surfaces
and a chamfered exterior surface.
[0020) FIG. 12 is a front view of a guard assembly incorporating various
features according to the present invention, including a two piece bail.
DETAILED DESCRIPTION OF THE DRAWIt~IGS AND THE
PRESENTLY PREFERRED EMBODIMENTS
(0021 ] While this invention is susceptible of several different embodiments,
this specification and the accompanying drawings disclose only some specific
forms as examples of the invention, including the most preferred embodiment.
The invention is not intended to be limited by the descriptions in this
specification
or the drawings. Instead, the scope of the invention is provided in the
claims.
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[0022) FIG. 1 shows a table saw (i0) having the improved riving knife/guard
assembly (20). The table saw includes a table top (12). The table top (12)
includes a slot (14). A saw blade (16) is conventionally mounted to a motor
and
carriage (both not shown) that is located under the table top ( 12). The saw
blade
( 16) protrudes through the slot ( 14). The portion of the blade ( 16) that
protrudes
through the slot ( 14) is the operative portion for cutting a workpiece (not
shown).
[0023] A riving knife or splitter (22) is also mounted to the table saw. The
riving knife (22) preferably is mounted to the carriage (not shown) under the
table
top ( 12) in such a manner so that it is centered behind or aligned with the
saw
blade ( 16). Since the carriage is the same as that on which the saw blade (
16) is
mounted, adjustment of the height or angle of the saw blade ( 16) will result
in an
identical adjustment in height or angle to the riving knife (22).
Alternatively, the
riving knife (22) can be fixedly mounted to a portion of the frame other than
the
carriage so that tllc riving knife (22) is Iwt adjustable with the saw blade
(16). The
riving knife (22) operates to keep the cut portion of the workpiece split or
separated after it is cut and as the remainder of the workpiece is fed through
the
saw blade (16). Splitting or keeping the cut portions of the workpiece
separated
helps to prevent potential binding of the saw blade ( I 6) during operation.
Optimally, the riving knife (22) is spaced approximately 1/~ inch from the saw
blade ( 16} to reduce the possibility for binding and kickback. Additionally,
it is
preferred that the riving knife (22) be at a height slightly lower than the
saw blade
( 16) height. This allows the riving knife (22) to be left in place for non-
through
cuts.
[0024] A guard (24), as explained in more detail below, is attached to the
riving knife (22). The guard includes a housing or guard top plate (26). The
guard
top plate (26} comes down around the blade (16) to protect the operator from
contacting the blade (16). Because the guard (24) is attached to the riving
knife
(22), the workpiece does not come into contact with the guard top plate (26).
The
guard top plate (26) preferably has a viewing slot (28) at its front end. The
front
end is the end where the workpiece is fed into the table saw ( 10). The
viewing slot
(28) provides the operator with increased visibility of the work zone or
cutting
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~.~ne ac well ac the wnrkPiece being cut, the saw blade (I6), and any
alignment
markings or scale (noi shown) on the table top {12) in the work zone. The use
of
alignment markings and a scale are conventional in the table saw industry. The
guard top plate (26) also has interior chamfered edges (30) at its front
portion, i.e.,
the workpiece feed portion of the guard top plate (lfi). The chamfered edges
(3U)
serve several purposes. The chamfered edges (30) increase the view of the
cutting
zone, as well as the blade {16) and workpiece, while maximizing the distance
from
the blade ( 16) to the operator. Further, they facilitate better light
dispersion from
an on board light (described below). As shown in FIG. 1 l, the outside edges
(30')
of the guard top plate may also be chamfered. While FIG. I 1 only illusri-ates
one
outside edge (30') that is chamfered, both may be chamfered. The chamfered
rnct~ide edge ('iO') helpc to maximize the range of useficl height for beveled
cuts
without having to remove the guard (24).
(0025) Additionally, the blade (16) may be recessed in the guard (24). Thus,
when the guard top plate (26) is placed just above the height of the workpiece
to
be cut, the blade ( 16) will automatically be at the correct height for the
cut.
(0026) The guard (24) may also include a bait (32). The bail (32) is pivotally
mounted (36} to the guard top plate (26). The bail is also shaped so that when
the
workpiece being cut is moved towards the blade (I6}, the bail {32) rides over
the
workpiece to allow the workpiece to move into the cutting zone. The
combination
of the bail's (32) shape along with the pivot mounting (36), allows fox this
to
occur. The arc-shaped bail (32) shown in FIG. 1 will offer very little
resistance
when feeding the workpiece, and will also reduce the forces that tend to make
the
guard top plate (26) flex during use so that the guard top plate (26) does not
hit the
blade (16) or interfere with the cutting operation. As can best be seen in
FIGS. l,
2 and 5, the bail (32) has sides (38, 40) that extend beyond the sides of the
guard
top plate (26). The sides (38, 40) provide protection from the blade (16) both
before and after the cut. Likewise, the bail (32) has a front portion (42)
that will
contact an operator's hands or fingers that are on top of the workpiece as it
is fed
to be cut, thus giving a warning that the operator's hands or fingers may be
coming near the blade (16). The bail (32) is also designed not to interfere
with
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measuring, aligning or setting up the wnrkpiece due to its pivotal mountinb
(36).
Specifically, as shown in FIG. 4, the bail (32) can be lifted and rotated back
onto a
pair of stops (34} located on either side of the guard top plate (26). The
guard top
plate (26) wilt remain in place even when the bail (32) is lifted into a
raised or up
position from its lowered or down position. As shown m 1-~'ig. S, the bail
(32) has
stub ends (44) that fit into stub receiving orifices (46) (only one is shown)
for
pivotally mounting (36) the bail (32) to the guard top plate {26). The
utilization of
the stub ends (44) and stub receiving orifices (46) allows the bail (32} to be
removed and attached to the guard top plate (26) without the use of any tools.
[0027] An alternate bail (32') is shown in FIG. 12. The bail (32') operates
and
functions similar to the bail (32) except that it is two distinct pieces.
Specifically,
bail 32'has a left side piece (70) and a right. side piece (72). The two
separate side
pieces (70, 72) can be raised or lowered into the up or down position
independently. This two-piece construction provides greater flexibility for
adjustments and accommodating different size and shape workpieces.
[0028] The guard (24) is mounted to the riving knife (22) through a system of
pins and slots. FIG. 5 shows that in the preferred embodiment, two pins and
two
slots are used. The first pin is a mufti-position pin (4:8) having a lever or
arm (50)
for adjusting the position of the mufti-position pin (48). The mufti-position
pin
(48) further includes a u-shaped or bent section (52) as best shown in FIGS.
5, 7
and 8. A second pin (54) is also used in the preferred embodiment. The second
pin (54) is mounted to the guard top plate (26) in the preferred embodiment by
press fitting the pin (54) into the bottom side of the guard top plate (26).
Specifically, a channel (56) is provided at the back end (i.e., not the
workpiece
feed end) of the guard top plate (26), and the second pin (54) is press fit
into the
channel (56). Other methods for attaching the second pin (54) are also
acceptable.
As shown in FIGS. 5 and 7, the mufti-position pin (48) is mounted to the
bottom
side of the guard top plate (26) through the use of two screws (58) and
washers
(60). Again, other methods for mounting the mufti-position pin (48) are
acceptable. The riving knife {22) includes slots (62, 64) For receiving the
multi-
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position pin (50) and the second pin (54). The slots (62, 64) arc dogleg
shaped
and are set in opposing directions as best shown in FIG. S.
[0029[ The mufti-position pin (50) is capable of being moved into at least two
positions. tn a first or secure position, the guard {24) is securely mounted
to the
riving knife (22). The first position is clearly shown in PIG. 8. In the first
position, the bent or u-shaped section (52) of the mufti-position pin is
secured in
the dogleg portion of the slot (62). Likewise, the second pin (54) is also
secured in
the dogleg portion of the second slot (64). When in this position, pressure is
exerted in the front, back, upward, and downward directions. As a result, the
guard (24) is securely attached to the riving knife (22) and ready for
operation. In
the second or release position, the bent or u-shaped section (52) of the multi-
position pin is generally located in the non-dogleg portion of the slot (62)
and the
pressure exerted during the first position is generally relieved. This allows
the
guard to be lifted, thus removing the mufti-position pin (48) from slot (62)
and the
second pin (54) from slot (64). It is acceptable to reverse the positions of
the
mufti-position pin {48) and the second pin (54) so that the mufti-position pin
(48)
is located at the back end of the guard top plate (26} and the second pin (54)
is
located at the front end of the guard top plate (26).
[0030] The guard (24) is capable of being attached to and removed from the
riving knife (22) without the use of any tools. When attaching the guard (24)
to
the riving knife (22), the lever (50) initially should be in a vertical
position so that
it is perpendicular or near perpendicular to the guard tap plate (26). When
the
lever (50) is in this position, the bent or u-shaped section (52) is also
perpendicular
or near perpendicular to the guard top plate (26) as shown in FIG. 9. The
second
pin (54) is placed in slot (G4) and ti~C taut or u-shaped section (52) of
multi-
position pin (48) is placed in slot (62). The lever (50) is engaged downwardly
toward the table top (12) to move the mufti-position pin (48} to the first
position.
As the lever (50) is engaged, the bent or u-shaped section (52) is also
rotated so
that it moves into the dogleg section of slot {62). As the mufti-position pin
{48)
moves into the dogleg slot (62), the guard (24) is forced toward the backside
of the
table saw (10) and the second pin {54) is moved into the dogleg section of
slot
.u-. _. *., ~ ~... a n, x . an ..~~ ~ , kx _..... ~ .-.... , .~.<., ~~"w.~~
,".~*".~~M": ~;.~.~..~,~ ~,~~.. ~ y....,w.~ .__
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(64). Thin, when the mufti-position pin (48) is in the first position (as best
shown
in FIGS. 7 and 8), the guard (24) is securely attached to the riving knife
(22).
Additionally, the lever (SO) may be secured by tucking the handle portion (66)
of
the lever (50) below the guard top plate (26) as shown in FIG. 7. A securing
post
(68) as shown in FIGS. 5 and 7 can be used to further aid in securing the
lever {SO)
on the under side of the guard top plate (26) while the mufti-position pin
(48) is in
the first position. Securing the Lever (50} under the guard top plate (26) as
well as
use of the securing post (68) helps eliminate accidental disengagement of the
mufti-position pin (48) to the second position.
[0031] The mufti-position pin {48) must be moved to the second position
(described above and shown in FIG. 9) in order to be able to remove the guard
(24) from the riving knife (22). Specifically, in the preferred embodiment,
the
mufti-position pin {48) is moved to the second position by moving the lever
(50)
first in a downward direction, then horizontally outward, and finally upward.
This
motion places the mufti-position pin (48} in the second position and allows
the
guard (24) to be removed from the riving knife (22}~. ~f course, other Lever
motions are acceptable depending on whether any additional or different
securing
devices are used. For example, the securing post (68) could alternatively be
mounted on the side of the guard top plate (26) and the lever (50) could be
structured to engage a side mounted securing post. Many other alternatives are
also available.
j0032] The guard (24) preferably may also include a light (74) and a
magnifying lens (76) as shown in FIG. 10, although neither is required. The
light
(74) can be either incandescent, halogen, LED or any other acceptable light
and is
oriented to illuminate the cutting none as well as the wvrkpiee;c, saw blade
(16)
and any scale or alignment marks on the table top ( 12). The light (74) is
mounted
to the guard top plate (26) preferably in the viewing slot (28), and can be
powered
by wiring to the table saw (10) power source or through the use of a battery.
The
light (74) may be turned on and off with a switch or button (78), or may be
directly wired to turn on and off in conjunction with turning on and off the
saw
blade (16).
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[0033) The magnifying lens (76) is preferably adjustably mounted to top side
of the guard top plate (26) through the use of guide rails (80) as shown in
FIG. 10.
The guide rails (80) in FIG. 10 are fastened to the guard top plate (26) by
recessed
screws (82). However, other methods for forming the guide rails (80) are
acceptable such as gluing, or molding the guide rails (?SU) directly into the
guard
top plate (26). The guide rails (80) may also be located at different sections
ofthe
guard top plate (26) such as in the middle or tower portions. The guide rails
(80)
allow the position of the magnifying lens (76) to be adjusted by sliding the
lens
(76) in the guide rails (80). The magnifying lens ( rb) can provide an
enlarged
view of the cutting zone as well as the workpiece, the blade ( 16) and the
scale or
alignment marks on the table top (12). This will aid in improved set up for
the cut.
[0034) The guard (24.) may also be used in an active guard system.
Specifically, the guard top plate (26) or the bail (32) could become part of a
touch
system that sets off audio or visual alarms to prevent injury. The active
system
could also activate a brake to stop the blade { i 6) or cut the power to the
motor that
drives the blade (I6). The operation and design of an active touch system is
described in pending United States provisional patent application number
60/444,263 (filed on January 31, 2003), which is hereby incorporated herein by
reference.
[0035] Finally, the guard (24) also could have a vacuum port incorporated in
the guard top plate (26). The port is attached to a vacuum source and will
remove
any dust or other loose matter that gathers under the guard top plate (26).
This
vacuum will prevent the accumulation of wood dust from cutting and will make
clean up easier and quicker.
[00361 The foregoing diseiosurc is the best mode devised by the inventors for
practicing this invention. It is apparent, however, that apparatus
incorporating
modifications and variations will be obvious to one skiiied in the art.
Inasmuch as
the foregoing disclosure is intended to enable one skilled in the pertinent
art to
practice the instant invention, it should not be construed to be limited
thereby but
should be construed to include aforementioned obvious variations and be
limited
only by the spirit and scope of the following claims.
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[0037] It is therefore intended that the foregoing detailed description be
regarded as illustrative rather than limiting, and that it be understood that
it is the
following claims, including atl equivalents, that are intended to define the
spirit
and scope of this invention.
